1. Technical Field
The present invention relates to electro-optical devices such as liquid crystal devices, methods for producing the same, and various electronic apparatuses including the same.
2. Related Art
A typical electro-optical device includes, as described in JP-A-2000-75320, an electro-optical material, such as liquid crystal, held between a pair of a thin-film transistor (TFT) array substrate and a counter substrate. In a pixel region where a plurality of pixels are arranged in a plane on the TFT array substrate, pixel electrodes for applying voltages to the liquid crystal are disposed in associated pixel portions. In addition, TFTs for switching ON and OFF the associated pixel electrodes and storage capacitors electrically connected to the TFTs along with the pixel electrodes are disposed in the associated pixel portions. In the specification, the “pixel region” may be referred to as an “image display region”.
According to a technique described in JP-A-2000-75320, the TFTs and the storage capacitors are arranged in the same layer in the associated pixel portions on the TFT array substrate. Alternatively, the storage capacitors and the TFTs may be arranged in the associated pixel portions on the TFT array substrate so that the storage capacitors lie in a layer above the TFTs and, as viewed in plan, the storage capacitors are superimposed on the TFTs.
In a process of producing such an electro-optical device, after the TFTs and the storage capacitors are formed, hydrogenation is performed over a semiconductor layer of each of the TFTs from an upper layer via the associated storage capacitor.
According to the structure in which the TFTs and the storage capacitors are arranged in the same layer in the associated pixel portions on the TFT array substrate, as viewed in plan on the TFT array substrate, the area of non-opening regions is increased whereas the area of opening regions is decreased because of the arrangement of the TFTs and the storage capacitors, resulting in a possible reduction in the aperture ratio. In contrast, according to the structure in which the storage capacitors lie in a layer above the TFTs in the associated pixel portions on the TFT array substrate, the aperture ratio can be improved. However, since the TFTs hide behind the shadows of the storage capacitors, as viewed in plan on the TFT array substrate, hydrogenation performed from an upper layer during the production of the electro-optical device is blocked by the storage capacitors, resulting in ineffective hydrogenation. As a result, the characteristics of the TFTs become unstable and are deteriorated, resulting in a reduction in yield in the process of producing the electro-optical device and possible deterioration of image quality.